This invention relates to a heavy-duty circuit breaker switch, for example, a gas current arc blow-out switch. In case the switch interrupts a high-intensity periodic current (for example, in excess of 40 kA) caused by a short circuit, the electric arc drawn between the movable and stationary contacts is particularly powerful. In known circuit breakers, the separation of contacts is effected when a predetermined current intensity is exceeded; regarding the extinguishability of the arc an optimum moment of current interruption related to the momentary amplitude of the high-intensity periodic current has not been considered or taken into account.